Note the following problems: 1. " max_row <- (1:nrow(df))[which.max(df$Amount)]"
This is a bit silly. max_row <- which.max(df$Amount) will do. See ?which.max 2. What happens if the max is the first or last row? e.g. > dat <- data.frame(a=runif(5),b=1:5) > max_row<- which.max(dat$b) > mean(dat[max_row+c(-1,0,1),"b"]) ## 2-d indexing [1] NA Cheers, Bert Gunter "Data is not information. Information is not knowledge. And knowledge is certainly not wisdom." -- Clifford Stoll On Mon, Sep 21, 2015 at 10:51 AM, Mark Sharp <msh...@txbiomed.org> wrote: > Nico, > > I expect there are many better ways to do this, but this does work: > max_row <- (1:nrow(df))[which.max(df$Amount)] > mean(df$Amount[max_row + c(-1, 0, 1)]) > >> max_row <- (1:nrow(df))[which.max(df$Amount)] >> mean(df$Amount[max_row + c(-1, 0, 1)]) > [1] 151.6667 > > R. Mark Sharp, Ph.D. > Director of Primate Records Database > Southwest National Primate Research Center > Texas Biomedical Research Institute > P.O. Box 760549 > San Antonio, TX 78245-0549 > Telephone: (210)258-9476 > e-mail: msh...@txbiomed.org > > > > >> On Sep 21, 2015, at 9:52 AM, Nico Gutierrez <nico.gutierr...@gmail.com> >> wrote: >> >> Hi All, >> >> I need to do the following operation from data.frame: >> >> df <- data.frame(Year = c("2001", "2002", "2003", "2004", "2005", "2006", >> "2007"), Amount = c(150, 120, 175, 160, 120, 105, 135)) >> df[which.max(df$Amount),] #to extract row with max Amount. >> >> Now I need to do 3 years average around the max Amount value (ie: >> mean(120,175,160)) >> >> Thanks! >> N >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.